Image Forming System Paper Discharge Alignment Control
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Solution Overview
Problem
High-speed and high-volume printing systems face challenges in aligning print sheets accurately without enlarging the paper discharge device, particularly with thin papers that lack firmness, leading to misalignment and pile collapse.
Innovation Solution
An image forming system with a paper discharge device equipped with an aligning unit that independently aligns the front and rear ends and side ends of print sheets, and an elevation unit that adjusts the paper discharge table height, controlled by a unit that synchronizes paper feed and printing operations with aligning and elevation operations to prevent misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If fences for alignment are fixedly provided in slightly expanded positions from the size of the print sheet, then the space surrounded by the fences is wider than the print sheet size, but print sheet alignment cannot be smoothly performed since the paper discharge condition is not stabilized
Solution Approach 1:
The patent applies the dynamics principle by making the fences movable rather than fixed. The front fence and rear fence can independently move in the paper discharge direction, allowing the system to adapt to different paper types and discharge conditions. This dynamic adjustment capability enables precise alignment while accommodating variations in paper behavior during discharge.
Solution Approach 2:
The patent implements parameter changes by allowing the fences to adjust their positions based on paper characteristics and discharge speed. The control unit modifies the fence positions dynamically to optimize alignment for different paper types (e.g., thin paper vs. thick paper) and discharge conditions, thereby maintaining high alignment accuracy across varying operational parameters.
2Adaptability or versatility
If the discharged print sheet is thin paper (basis weight less than about 50 g/m2), then the print sheet lacks firmness and leans against the fence, but the next print sheet is stacked on the print sheet partially placed on the fence causing misalignment
Solution Approach 1:
The patent uses the dynamics principle to address thin paper handling by enabling the fences to move independently. When thin paper is detected, the system adjusts the fence positions and timing to prevent the paper from leaning against the fence. The front fence can be positioned to support thin paper without causing it to buckle, while the rear fence maintains proper spacing.
Solution Approach 2:
The patent applies preliminary action by adjusting the fence positions in advance based on paper type detection. Before thin paper enters the alignment zone, the fences are positioned to provide optimal support, preventing the paper from leaning or buckling. This proactive adjustment ensures that subsequent sheets are stacked correctly without misalignment.
3Speed
If an aligning operation is conducted in accordance with high-speed paper discharge, then alignment can be achieved, but it is necessary to enlarge the fence driving motor which enlarges the entire device
Solution Approach 1:
The patent applies segmentation by dividing the alignment function into independent front and rear fences that can move separately. This segmentation allows each fence to be driven by smaller, more compact motors rather than requiring one large motor to move both fences simultaneously. The independent movement capability enables high-speed alignment with reduced motor size and overall device footprint.
Solution Approach 2:
The patent implements parameter changes by optimizing the fence driving system for high-speed operation with smaller motors. The control unit coordinates the movement of front and rear fences with precise timing and velocity control, enabling effective alignment at high paper discharge speeds without requiring excessive motor power or large device dimensions.
Data Source
AI summary
In execution of aligning operation in a paper discharge device, every time the number of discharged print sheets reaches the number of aligning-start print sheets, a control unit performs aligning operation while the unit intermittently drives paper feed rollers of an image forming apparatus, to prevent discharge of a print-completed print sheet to a paper discharge table during aligning operation. Further, the control unit intermittently drives an elevation unit such that the print sheet on the top of a paper discharge table is always lower than a paper discharge position of a pair of paper discharge rollers. In execution of high-speed and high-volume printing, it is possible to perform alignment of the print sheet discharged on the paper discharge table without reducing productivity.